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Fake Ruby?
  
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Mathias




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PostPosted: Jun 02, 2019 09:07    Post subject: Fake Ruby?  

Here's another doubtful specimen; Corundum var. Ruby. Fom India.

I bought the specimen yesterday, from a collector who stopped. He told me that he suspects a fake, glued ruby. I bought it anyway (of course for a bargain).

The size is about 6 cm, left to right, 2 cm thick crystals.

At home I tried to break the crystals apart, but even force didn't split them up.
If these crystals are glued, then the person who did it used incredible strong glue.

There's also no trace of glue visible. So the forger did a wonderful job.

Or could it be that these 2 crystals grew naturally?

Thanks,
Mathias



523E.JPG
 Mineral: Corundum
 Dimensions: 6*5 cm
 Description:
 Viewed:  1604 Time(s)

523E.JPG



523I.JPG
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523I.JPG



523G.JPG
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523G.JPG


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David K. Joyce




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PostPosted: Jun 02, 2019 09:18    Post subject: Re: Fake Ruby?  

Why do you think the join has been faked? Crystals form attached
together all the time. If there is no trace of glue and if the light coloured material is, in fact, mineral. then the two crystals probably formed together. Use a U/V lamp as an additional way to try to detect glue, most of which are fluorescent. DKJ
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Mathias




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PostPosted: Jun 02, 2019 09:27    Post subject: Re: Fake Ruby?  

David thanks, I though it was glued because you would expect the crystal edges would be aligned from one to the other crystal. Moreover I could find any photos (google) of similar specimen.
Thanks,
Mathias.
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Bob Carnein




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PostPosted: Jun 02, 2019 09:41    Post subject: Re: Fake Ruby?  

As suggested by Mr. Joyce, a fluorescence test definitely would help. In the last photo, the crystals appear to be intergrown. It would be very difficult to "fake" this, and it seems doubtful that anybody would attempt it on a specimen that you yourself said was relatively inexpensive. Also, the juncture appears to contain material similar to what's seen in the cracks parallel to the basal pinacoid.on the left-hand crystal. Crystal edges might be aligned if this was a twin, but it may just be a random intergrowth. Note that parting surfaces in the two crystals are also not aligned.
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Pete Richards
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PostPosted: Jun 02, 2019 11:48    Post subject: Re: Fake Ruby?  

The first image does suggest a twinned crystal, though the other two really don't - there is no reason for one half of a twin to show part of a termination adjacent to the twin plane.

Twinning is known in corundum, on {10-11} for those who understand Miller indices. What is important is that true twinn would have a much more acute angle between the two halves. And it might be expected to lead to a distorted shape. Here is a figure from Dana's System, 7th edition, of a twin from South Africa, which shows the proper angle for the twin and also considerable flattening of the crystal due to the effects of twinning on the growth rates of various faces of the crystal.



IMG_5710.jpg
 Mineral: Corundum twin on {10-11}
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IMG_5710.jpg



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Matt_Zukowski
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PostPosted: Jun 02, 2019 13:01    Post subject: Re: Fake Ruby?  

Soak it in solvent and see if any glue dissolves.
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Peter Lemkin




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PostPosted: Jun 02, 2019 14:02    Post subject: Re: Fake Ruby?  

Matt_Zukowski wrote:
Soak it in solvent and see if any glue dissolves.


Acetone would do for super-glues. I'd also add I wish I had been offered such for a not-high price! I suspect it is not glued...but since you asked, it is fairly easy to find out. UV and then acetone.
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David K. Joyce




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PostPosted: Jun 02, 2019 15:24    Post subject: Re: Fake Ruby?  

Thanks for that Pete. I've never seen a twinned corundum! DKJ
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Tobi




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PostPosted: Jun 03, 2019 05:24    Post subject: Re: Fake Ruby?  

I don't have knowledge about twinning and Miller indices, but at least I know that it is not unsual that the rubys from that locality (the name is Mysore, https://www.mindat.org/loc-1999.html ) appear intergrown like that. Most of them are single crystals on matrix or fallen off, but I have seen such aggregates before. So I agree with the others that this is rather natural than fake ...
Mathias wrote:
At home I tried to break the crystals apart, but even force didn't split them up.
I'm glad you failed ;-)
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Peter Lemkin




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PostPosted: Jun 03, 2019 06:13    Post subject: Re: Fake Ruby?  

Tobi wrote:
I don't have knowledge about twinning and Miller indices, but at least I know that it is not unsual that the rubys from that locality (the name is Mysore, https://www.mindat.org/loc-1999.html ) appear intergrown like that. Most of them are single crystals on matrix or fallen off, but I have seen such aggregates before. So I agree with the others that this is rather natural than fake ...
Mathias wrote:
At home I tried to break the crystals apart, but even force didn't split them up.
I'm glad you failed ;-)


Ouch! I, myself, would not have put much force on them in case they were natural. Corundum is very hard and strong, but could have a natural fracture or weak spot. Modern glues can be VERY strong, so I still suggest the UV and acetone before you open the champagne....just to make sure [even if I agree with most here it is likely natural]. Acetone will certainly not hurt the corundum...but do it outside, as it could hurt you breathing it.
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Mathias




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PostPosted: Jun 03, 2019 11:57    Post subject: Re: Fake Ruby?  

I soaked it in Acetone for 30 minutes.
Still rock solid.....
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fuss




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PostPosted: Jun 19, 2019 00:01    Post subject: Re: Fake Ruby?  

try a Long wave UV light, should fluoresce brilliant red if its real.
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Bob Carnein




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PostPosted: Jun 19, 2019 08:52    Post subject: Re: Fake Ruby?  

Synthetic rubies also fluoresce in LWUV.
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John Betts




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PostPosted: Jun 19, 2019 20:48    Post subject: Re: Fake Ruby?  

Using LW or SW UV to detect glues no longer is applicable. Many modern adhesives are UV-curing and they work by absorbing the UV illumination.

I use UV-curing adhesive to restore Herkimer Diamond clusters. Testing with UV does not cause the glue to fluoresce - only inspection under a microscope will reveal the presence of glue.

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